Plant Breeding

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Introduction

Plant breeding started with the domestication of agricultural plants and with sedentary agriculture, a practice which is estimated to date back 9,000 to 11,000 years. Initially, early farmers simply selected food plants with some of the desirable characteristics.

It is found practicing worldwide by most individuals such as gardeners and farmers. It is also used by professional plant breeders who are employed by organizations such as government institutions, universities, crop-specific industry associations, or research centers. The process called participatory plant breeding is used by the farmers to involve in plant breeding continuously. International development agencies believe that breeding new crops is vital for ensuring food security by developing new varieties that are higher-yielding, disease-resistant, drought-tolerant, or regionally adapted to different environments and growing conditions.


Plant Breeding - Breeding For Disease Resistance Requires

Plant breeding is the science of adjusting the traits of plants so as to supply desired characteristics. The goals of plant breeding are to supply crop varieties that boost unique and superior traits for a spread of agricultural applications. Plant breeding also called crop breeding is often accomplished through many various techniques starting from simply selecting plants with desirable characteristics for propagation, to methods that make use of data of genetics and chromosomes, to more complex molecular techniques. Genes during a plant are what determine what sort of qualitative or quantitative traits it'll have. Plant breeders strive to make a selected outcome of plants and potentially new plant varieties. 


Types of Plant Breeding:

  1. Backcrossing

  2. Inbreeding

  3. Hybrid Breeding

  4. Mutation Breeding

  5. Genetic Engineering

Plant Breeding and Genetics

Gregor Mendel (1822–84) is taken into account as the "father of genetics". He has developed the laws of inheritance with the help of experiments with plant hybridization. Genetics stimulated research to enhance crop production through plant breeding.

Genetic modification of plants is achieved by adding a selected gene or genes to a plant, or by demolition of a gene with RNAi, to supply a desirable phenotype. The plants resulting from adding a gene are often mentioned as transgenic plants. If genetic modification genes of the species or of a crossable plant are used in check of their native promoter, then they're called cisgenic plants. Sometimes genetic modification can produce a plant with the specified trait or traits faster than classical breeding because the bulk of the plant's genome isn't altered.


Modern Plant Breeding

Modern plant breeding is applied genetics, covering biology, cytology, physiology, pathology, entomology, and statistics. It has also developed its own technology.

Sometimes many various genes can influence a desirable trait in plant breeding. The use of tools like molecular markers or DNA fingerprinting can map thousands of genes. This allows plant breeders to screen large populations of plants for people who possess the trait of interest. The screening is predicated on the presence or absence of a particular gene as determined by laboratory procedures, instead of on the visual identification of the expressed trait within the plant. 


Classical Plant Breeding or Conventional Plant Breeding

One major technique of plant breeding is selection, the method of selectively propagating plants with desirable characteristics and eliminating or "culling" those with less desirable characteristics.

Conventional breeding relies largely on homologous recombination between chromosomes to get genetic diversity. The classical plant breeder can also make use of various types of in vitro techniques such as protoplast fusion, embryo rescue, or mutagenesis to get diversity and produce hybrid plants that might not exist in nature.

Traits that breeders have tried to include into crop plants include:

  • Improved quality, like increased nutrition, improved flavor, or greater beauty

  • Increased yield of the crop

  • Increased tolerance of environmental pressures (salinity, heat, drought)

  • Resistance to viruses, fungi, and bacteria

  • Increased tolerance to insect pests

  • Increased tolerance of herbicides

  • Longer storage period for the harvested crop

Another technique is the deliberate interbreeding or of closely or distantly related individuals to supply new crop varieties or lines with desirable properties. Cross breeding plants are used to introduce traits or genes from one variety or line into a replacement genetic background. 


Issues and Concerns

Modern plant breeding, whether classical or through gene-splicing, comes with problems with concern, particularly with reference to food crops. The question of whether breeding can have a negative effect on nutritional value is central during this respect. A study published within the Journal of the American College of Nutrition in 2004, entitled Changes in USDA Food Composition Data for 43 Garden Crops, 1950 to 1999, compared nutritional analysis of vegetables wiped out 1950 and in 1999, and located substantial decreases in six of 13 nutrients measured, including 6% of protein and 38% of riboflavin. Reductions in calcium, phosphorus, iron, and vitamin C were also found.


Role of Plant Breeding in Organic Agriculture

Critics of organic agriculture claim it's too low-yielding to be a viable alternative to standard agriculture. However, part of that poor performance may be the result of growing poorly adapted varieties. Breeding varieties specifically adapted to the unique conditions of organic agriculture is critical for this sector to understand its full potential.

This requires selection for traits such as:

  • Water use efficiency

  • Nutrient use efficiency (particularly nitrogen and phosphorus)

  • Weed competitiveness

  • Tolerance of mechanical weed control

  • Pest or disease resistance

  • Abiotic stress tolerance (i.e. drought, salinity, etc...)

Plant breeding helps to enhance biodiversity. It has given the greatest benefit, by the usage of its products. Compared to any other techniques plant breeding is found to be simple where the process and the crop improvement ideas are simple. 

FAQ (Frequently Asked Questions)

1. Define Plant Mutation.

Ans: The mutations that can be found in plants are a natural phenomenon that helps the plants to change or alter the external characteristics or appearance.

2. What is Meant By Molecular Plant Breeding?

Ans: The changes that can be made at molecular levels of DNA to improve the characteristics. It includes processes such as genome selection, modern plant breeding, genetic engineering, etc.

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